<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <script>
    /*let show=function (a){
      return a*3;
    };*/
    let show=a=>a*3;

    alert(show(13));
    </script>
  </head>
  <body>
  </body>
</html>
